%0 Journal Article
%T Drug Release Kinetics from Polymer Matrix through Fractal Approximation of Motion
%A S. B£¿c£¿i£¿£¿
%A C. Ur£¿tu
%A M. Popa
%A A. Uliniuc
%A C. Peptu
%A M. Agop
%J Smart Materials Research
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/264609
%X The present paper analyzes the process of drug release from polymer matrix. This process has been considered as fractal polymer process. Since complexity of physical processes is replaced by fractality, the paper studies the process through fractal approach. In drug dynamics, fractal ¡°diffusion¡± equation can be obtained through fractal approximation of motion. All experimental release curves have been best demonstrated by Weibull relation (which was, in its turn, also demonstrated). Weibull parameters are related to the fractal dimension of drug release kinetics from a polymer matrix. Such a dimension can characterize and measure the complexity of the system. In the above-mentioned context, some experimental results of our researchers are presented and analyzed by comparing them with Peppas relation, a basic law in the description of drug release kinetics. Consequently, experimental data for Weibull relation are better correlated with certain resulting factors. At the same time, some conclusions regarding the phenomena involved in the process are considered as being based on the approach. 1. Introduction The adequate description of real, natural, and artificial objects is restricted by the mere use of Euclidean geometry, that is, the description of integer-dimensioned objects. In such perspective, this happens because numerous objects with noninteger dimensions, such as plants, galaxies, population patterns, and crystal growth, are left beyond analytical purpose. The characteristics of such objects can be described by means of fractal geometry [1, 2]. Natural and synthetic polymers considered as fractal objects are also included in the above category. Their main structural unit, the macromolecular coil, is known to be a fractal with typical fractal behavior [3¨C8]. The main idea of the paper focuses on this type of processes in which polymer fractality is responsible for drug release from various polymer matrixes. In what follows, we shall produce arguments to sustain the above statement. The experimental drug release kinetics indicate that drug loaded polymer matrix structures are thermodynamically unstable and evolve towards equilibrium. Specific parameters for each structure (drug type, incorporated drug dose(s), types and amounts of excipients, preparation technique, environmental conditions during drug release, and geometry and dimensions of drug delivery system) will lead to different evolutive trajectories, considered as consequences of internal collective processes. Thermodynamically nonbalanced processes generate the formation of fractal
%U http://www.hindawi.com/journals/smr/2012/264609/